Direct visualization of the vortex distributions in a superconducting film with a Penrose array of magnetic pinning centers: Symmetry induced giant vortex state

Abstract

Using scanning Hall probe microscopy a direct visualization of the flux distribution in a Pb film covering a fivefold Penrose array of Co dots is obtained. We demonstrate that stable vortex configurations can be found for fields H ∼ 0.8 H 1, H 1 and 1.6 H 1, where H 1 corresponds to one flux quantum per pinning site. The vortex pattern at 0.8 H 1 corresponds to one vacancy in one of the vertices of the thin tiles whereas at 1.6 H 1 the vortex structure can be associated with one interstitial vortex inside each thick tile. Strikingly, for H = 1.6 H 1 interstitial and pinned vortices arrange themselves in ring-like structures (“vortex corrals”) which favor the formation of a giant vortex state at their center.